Controlling professional VCR (s) for instance U-matic VCR(s), Beta-cam VCR(s) or S-VHS-VCR(s) through computers is known, as the said VCR(s) have in-built circuitry to be interfaced with computers. The said in-built circuitry is an integrated part of the system and is functional only with its own system. Furthermore, said VCR(s) are very expensive. Accordingly, there is no separate and independent circuitary with which any VHS-VCR(s) can be interfaced with the computer.
It is therefore, the object of this invention to provide interface in the form of PC Add-On Card between any VHS-VCR and computer for controlling VHS-VCR(s) through computer, thereby, avoiding the limits of the uses, programmability and costs.
To achieve the said objective, this invention provides AVI PC Add-On Card for controlling consumer grade VHS-VCR which comprises:
Address decoder section and bidirectional buffer connected to IBM expansion slot for exchange of information to and from the processor, PA1 Input/output (I/O) ports connected to bidirectional buffer, IBM expansion slot and address decoding section for controlling the functions of the VCR(s)and passing the status of the VCR(s) to the processor, PA1 Counter section connected to bidirectional butter, address decoding means, IBM expansion slot and (I/O) ports for counting the required number of tape positioning pulses and helping to determine the current status of the VCR(s), PA1 Digital switching control section connected to counter means through monostable multivibrator and also to (I/O) ports for giving the stop signal to Analog function switching control whenever terminal count is indicated or when required by the processor, PA1 Analog function switching control connected to I/O ports for switching all the functions of VCR's except stop function and digital switching control for switching stop function of VCR(s), PA1 Analog multiplexer section connected to said counter section, I/O ports, analog function switching control and VCR port(s) through VCR matrix(ces) for, PA1 passing tape positioning pulses to counter section, VCR status information to I/O ports, matrix input scan pulses to analog switching control and matrix(ces) output scan pulses to the VCR port(s), and PA1 receiving multiplex control signal from I/O ports, matrix output scan pulses from analog function switching control and matrix input scan pulses from VCR port(s). PA1 12/16 bit input port connected to 12/16 bit counter for passing the present count value of the 12/16 bit counter to the processor through bidirectional buffer. PA1 8 to 16 bit output port connected to analog function switching control and digital switching control through monostable multivibrator to control the switching of VCR's functions and audio/video port through audio/video switching control for selecting audio/video signals of VCR(s) or PC. PA1 8-bit input port connected to analog multiplexer section and the counter means for passing the status of VCR through bidirectional buffer, 4 to 8 bit output port connected to analog multiplexer section for selecting the VCR(s) to be controlled and 12/16 bit counter for controlling the functioning of 12/16 bit counter.
The IBM expansion slot is either 8 BIT or 16 BIT connector, and address decoder section consists of 3:8 decoder connected to 8 Bit comparator.
The counter section consists of .div.2/.div.25 counter, terminal count indicator, and configurable monostable multivibrator. The input of each of said instruments is connected to tape position pulses from said analog multiplexer section and the outputs to 12 Bit/16 Bit counter, digital switching control through monostable multivibrator and the processor through I/O ports respectively. Audio/Video ports are included through Audio/Video switch control to I/O ports for selecting Audio/Video signals of VCR or PC.
The I/O ports consists of:
The 12/16 bit counter is provided between .div.2/.div.25 counter and 12/16 bit input port for counting the number of tape position pulses from VCR(s) and is controlled by 4 to 8 bit output port.
Astable multivibrator is also connected to configurable monostable multivibrator for providing reference clock which helps in determining the status of VCR.
The invention will now be described with reference to the accompanying drawings:
FIG. 1 shows the block diagram of Analog Video Interactive (AVI) PC Add-On Card for controlling consumer grade VHS-VCR according to this invention.
FIG. 2 shows the block diagram of Analog Video Interactive (AVI) PC Add-On Card for controlling consumer grade VHS-VCR with audio/video switching control and audio/video port according to this invention.
FIG. 3 shows the Analog Video interactive equipment using the PC Add-On Card according to this invention.